I am Feike Visser (based in The Netherlands), Adobe consultant since 2007. Also quite active on twitter via @heervisscherHappy to help/support people with AEM-questions.
You can mix both if you want.With model-classes you can make them more reusable, and less code to get services etc.WcmUsePojo makes it easy to start with coding, but it is bound to the UI
I would not use the <div> in the head, because it will generate invalid HTML.See this : /libs/wcm/foundation/components/page/page.htmlthis will have all the logic: <head data-sly-include="head.html"></head>